Ncert – class 8- science – Chapter 10: Sound 2 Welcome to your Ncert - class 8- science - Chapter 10: Sound 2 1. A chain of hydrogen bombs is being exploded every time in the sun due to the fusion process, yet you do not hear the sound, because. The sound so generated dissipates away The sun is very far away The space between the sun and the earth is void The sound so generated is absorbed by various layers of the sun None 2. The safe limit of loudness of audible sound is above 80 db above 120 db 120 db 0 to 80 db None 3. A musical instrument is producing a continuous note. This note can not be heard by a person having a normal hearing range. This note must then be passing through: empty vessel wax water vacuum None 4. Sound waves having the following frequency are audible to human beings: 5000 cycles/sec 27000 cycles/sec 50,000 cycles/sec 5 cycles/sec None 5. Match the following columns and select the correct option from the codes given below.Column IColumn II(i) Pressure(p) Pattern formed due to multiple reflections(ii) Decibel(q) Unit of loudness(iii) Richter(r) Force per unit area(iv) Kaleidoscope(s) Scale to measure the intensity of (i) - (p), (ii) - (r), (iii) - (s), (iv) - (q) (i) - (q), (ii) - (p), (iii) - (s), (iv) - (r) (i) - (p), (ii) - (s), (iii) - (r), (iv) - (q) (i) - (r), (ii) - (q), (iii) - (s), (iv) - (p) None 6. A sound wave, whose time period is 3 s passes through a medium for 30 s. The number of waves that had passed through is: 3 waves 5 waves 10 waves 1 wave None 7. A sound wave has a speed of 200 m/s in a medium and it travels a distance of 1 m. What is the time taken by the wave to cross the medium 10 ms 50 ms 5 ms 100 ms None 8. The loudness of sound is determined by the Product of amplitude and frequency of vibration Frequency of vibration Amplitude of vibration The ratio of amplitude and frequency of vibration None 9. A particle takes 0.01 s to complete 5 vibrations, what is its frequency 500Hz 5 Hz 10Hz 50Hz None 10. A particle completes one vibration in 2 secs. How long does it take to vibrate 25 vibrations 50 sec 5 sec 10 sec 25 sec None 11. Name the instruments for which more than one part is responsible for the production of sound. All of the above Guitar Tabla Violin None 12. An astronaut can not hear his companion's sound at the surface of moon because: none of the above temperature is too low during night and high during day produced frequencies are above the audio frequency sound wave does not propagate through vaccum None 13. The maximum displacement of a particle in a vibratory motion is known as Time period frequency Amplitude Wavelength None 14. Which of the following vibrating parts of instrument is not matched with the respective instrument None of the above Drum- Stretched Membrane Tabla - Stretched Membrane Mridangam - Stretched Membrane None 15. Which of the following vibrates when a musical note is produced by the cymbals in an orchestra? Stretched membranes Metal plates Air columns Stretched strings None Time's up Please Share This Share this content Opens in a new window Opens in a new window Opens in a new window Opens in a new window Opens in a new window Opens in a new window Opens in a new window Opens in a new window Opens in a new window Opens in a new window Leave a Reply Cancel replyCommentEnter your name or username to commentEnter your email address to commentEnter your website URL (optional) Save my name, email, and website in this browser for the next time I comment.
